I have been running 8.5's in Grand Nationals for years and have one in my Firebird now. Price wise it really depends on what type of application you putting it in. If you are looking for a first gen F body/Nova style leaf spring rear they are pretty plentiful and cheap. If you are looking for the G body style they are more expensive because them only came in turbo Buicks and Hurst/Olds. I like the 8.5's and have had good luck with them. I have made many 10 second 1/4 mile passes on bone stock 8.5's but once you get your 60's down past 1.5's they do need an axle upgrade( I found that out the hard way! ) if you are using the rear in a heavy car like I was. I know a guy over on the turbo Buick board that has a stock 8.5 with stock replacement Moser C-clip style axles that has run 9.21 in the 1/4 with a 1.36 60' time on the stock gear and posi.

the 8.5's were in all the g-bodys steve88 said except the 84' hurst Olds. The cost to set up depends on Your goals. Strange has spool/axle packages for around $650 with c-clip eleminators,I use Motive "performance" series gears with good results(not the street gears), they're a little under $200. The g-body rears are getting harder to find & You can use the 8.5's from the 73-76 gm cars, with custom control arms & the right back spaced wheel & moving the shock mounts. http://www.maliburacing.com/iceman This is Rick Fisher in monnett area, He should be able to make the arms You need(although I've never used him, I've heard nothing but good about him). I have many passes in the 1.3's in the 60' with my 8.5 from a '73 car. once your 60's get in the 1.4's Your gonna need an anti roll bar installed, as the g-body's twist up pretty bad.